Secondary ignition wire end assembly



March 4, 1969 c. D. SCHRADER ET 3,431,534 SECONDARY IGNITION WIRE END ASSEMBLY Filed Sept. 6. 1966 v V .7 V

Che/files 0. .Sc/rrader Wax A. .SchradeqSz INVENTORS United States Patent 2 Claims ABSTRACT OF THE DISCLOSURE A secondary ignition wire end assembly defined by a conductive, stiff and resilient coil spring tightly threaded onto the dielectric resilient covering of one end of a secondary ignition wire with several convolutions of the coil spring passing over a backturned exposed end of the conductive core of the ignition wire and at least the endmost convolution of the spring threadedly engaged with the ignition wire inwardly deflected and tightly frictionally engaged with the resilient outer covering of the ignition wire so as to prevent axial as well as rotational shifting of the coil spring relative to the ignition wire covering. The coil spring includes a free end projecting outwardly beyond the ignition wire for telescopic engagement over a spark plug terminal and the endmost convolution of the free end of the spring is inwardly deflected for tight frictional engagement with and biting into a diametrically reduced portion of the spark plug terminal with which the free end of the coil spring is engaged.

This invention relates to a novel and useful wire end assembly and more specifically to a wire end assembly specifically adapted for use on an internal combustion engine secondary ignition wire. The end assembly of the instant invention may be utilized on either end of a spark plug wire for the purpose of establishing a good electrical connection between the spark plug wire and an associated spark plug and also between a spark plug wire and the associated distributor cap terminal. Still further, the wire end assembly of the instant invention may also be utilized on either or both ends of the secondary coil wire extending from the coil to the center electrode of an associated distributor cap.

The main object of this invention is to provide a secondary ignition wire end assembly which may be utilized to establish a good electrical connection between a secondary ignition wire conductive core and an associated terminal of an engine ignition component.

Another object of this invention is to provide a wire end assembly in accordance with the preceding object and which will be readily disengageable from the associated terminal of an engine ignition component.

Still another object of this invention is to provide a wire end assembly which is readily engageable with a terminal of an associated engine ignition component and which is adapted to have a dielectric weather protective terminal cap operatively associated therewith.

A final object of this invention to be specifically enumerated herein is to provide an ignition wire end assembly in accordance with the preceding objects which will conform to conventional forms of manufacture, be of simple construction and easy to use so as to provide a device that will be economically feasible, long lasting and relatively trouble-free in operation.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

Patented Mar. 4, 1969 FIGURE 1 is a fragmentary perspective view of a conventional form of V-type internal combustion engine illustrating the wire end assembly of the instant invention operatively associated with the various end portions of the secondary ignition wires of the ignition system of the engine;

FIGURE 2 is an enlarged fragmentary vertical sectional view taken substantially upon a plane passing through one of the spark plug bores of the internal combustion engine and illustrating the associated wire end assembly in longitudinal section; and

FIGURE 3 is a fragmentary enlarged longitudinal sectional view of another wire end assembly of the instant invention operatively associated with the output terminal of the coil of the internal combustion engine.

Referring now more specifically to the drawings, the numeral 10 generally designates a conventional form of internal combustion engine including a pair of cylinder heads, one of which is generall designated by the reference numeral 12, and a distributor assembly generally referred to by the reference numeral 14 and including a conventional form of distributor cap 16. The cylinder head 12 includes a plurality of threaded spark plug bores 18 in which corresponding spark plugs 20 are threadedly engaged.

Each of the spark plugs 20 includes a center electrode 22 whose upper end 24 defines an electrical terminal there for. The terminals 24 each include a diametrically reduced portion 26 and each is electrically connected to the associated distributor cap terminal by means of a secondary ignition wire 28. In addition, a further secondary ignition wire 29 extends between the center distributor cap terminal (not shown) and the output terminal 30 of the coil 32 of the internal combustion engine 10.

The output terminal 30 of the coil 32 is defined by a conductive cup or sleeve 34 including an end wall 36 and which is recessed in a boss 38 carried by the coil 32 and having a bore 40 formed therein in which the sleeve 34 is secured. The center terminal of the distributor cap 16 as well as the eight outer terminals of the distributor cap 16 with which the secondary ignition wires 28 are connected are constructed in substantially the same manner as the output terminal 30 of the coil 32 and are hence not specifically illustrated.

The secondary ignition Wire 28 includes a conductive and flexible inner core 42 covered by a flexible and dielectric covering 44 of resilient material such as rubber or the like. All of the spark plug ends of the ignition wires 28 are constructed as illustrated in FIGURE 2 of the dawings and both ends of the ignition wire 29 and the distributor cap ends of the ignition wires 28 are constructed as illustrated in FIGURE 3.

The spark plug end of each ignition wire 28 has the core 42 projecting outwardly of the covering 44 and bent back upon the outer surface of the covering 44 as at 46. Then, one end portion of a coil spring-type terminal 48 has a plurality of its convolutions tightly wound about the covering 44 and over the backturned end portion of the core 42. Of course, the convolutions of the terminal 48 are not Wound about the covering 44 when applying the te minal 48 to the ignition wire 28, but the corresponding end of the terminal 48 is threaded onto the end of the ignition wire 28. In addition, the extreme terminal end of the terminal 48 includes an inturned terminal end 50 which bites into the covering 44 and thus resists both rotational and axial displacement of the terminal 48 rela tive to the ignition wire 28.

The end of the terminal 48 remote from the ignition wire 28 is slipped over the terminal 24 in the manner illustrated in FIGURE 2 of the drawings and also includes an inturned terminal end portion 50 which is seated and at 56 to form a waterproof seal between the inner core 42 of the wire 28 and the terminal 24.

The opposite end of the ignition wire 29 and the ends of the ignition wires 28 remote from the spark plugs 20 are constructed in substantially the same manner except that the coil spring-type terminals 60 secured thereto are somewhat shorter than the terminals 48 and the cups 62 are also shorter than the cups or sleeves 52. Further, the free ends of the terminals 60 include ou-tturned terminal end portions 64 in lieu of inturned terminal end portions and therefore bite into the terminals in which they are telescoped.

While the Wire end assembly has been illustrated as being utilized on a motor vehicle engine, it is to be understood that it can be used on any secondary ignition wire such as ignition wires on tractors, lawn mowers, chain saws, outboard motors and industrial engines, etc.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1. In combination with a spark plug of the type including a center electrode with one outer end portion thereof exposed and defining an electrical terminal provided with a diametrically reduced portion adjacent but spaced from the outer end face of the electrical terminal, a secondary ignition wire end assembly comprising a secondary ignition cable including an inner conductive core covered by an outer resilient insulative cover, said conductive core having one end projecting outwardly of the corresponding end of said cover, a substantially constant diameter, conductive and resilient coil spring-type of terminal having one end portion thereof tightly wound about said corresponding end of said cover and the other end portion projecting outwardly of said corresponding end, said other end portion of said terminal being snugly telescoped over said electrical terminal, said one end of said core being bent back upon itself over the outer surface of the corresponding end of said cover and a plurality of convolutions of said one end portion of said coil spring-type of terminal being wound tightly thereover, the terminal end of said one end portion of said coil spring-type of terminal being slightly laterally inwardly deflected for tighter frictional engagement with the adjacent portion of said cover thereby resisting rotational as well as axial displacement of said coil spring-type of terminal relative to said cover, and the terminal end of said other end portion of said coil spring-type of terminal being also inwardly deflected and tightly frictionally engaged with and at least partiall impaling and biting into the outer surface portion of said diametrically reduced portion of said spark plug electrical terminal.

2. The combination of claim 1 including a tabular dielectric terminal cap telescoped over said cover at said electrical point spaced therealong from said coil springtype of terminal, opening toward and at least substantially entirely enclosing said coil spring-type of terminal and adapted to provide a substantially weather-tight seal between said cover and a terminal with which said coil spring-type of terminal is engaged.

References Cited UNITED STATES PATENTS 257,865 5/1882 Hamilton 339-223 1,334,040 3/1920 Lee 339-223 2,792,560 5/1957 Bollrneier 33967 2,835,724 5/1958 Colbert 33926 XR 2,904,769 9/1959 Sampson et al 339-26 FOREIGN PATENTS 17,003 1934 Australia. 71,570 7/1959 France.

MARVIN A. CHAMPION, Primary Examiner.

PATRICK A. CLIFFORD, Assistant Examiner.

US. Cl. X.R. 339256 

